DRY-FARMING.pptx

ABOUT DRY FARMING LAND

1. Pandit jawaharlal nehru college of agriculture and research institute – karaikal 609603 COURCE TITLE: agron 501 Modern concepts in crop production (3+0) COURCE TEACHER: Dr.R . MOHAN TOPIC: dry farming BY, R.VIMALRAJ

2. Topics for discussion Dryland agriculture Definition of dry farming, dry land and rainfed farming Why dry farming is important ? Characters of dry farming Problems of crop production in dry farming Benefits of dry farming Moisture stress and effects of moisture stress

3. Mechanisms to conserve water Mechanism to improve water uptake Drought tolerance Resource development and utilization Dryland farming techniques Dry farming practices Conclusion

4. Dryland agriculture Growing of crops entirely under rainfed conditions is known as dryland agriculture. Depending on the amount of rainfall received , dryland agriculture can he grouped into three categories;

5. Dry farming Dry farming is cultivation of crops in regions with annual rainfall less than 750 mm . Crop failure is most common due to prolonged dry spells during the crop period. These are arid regions with a growing season (period of adequate soil moisture) less than 75 days. Moisture conservation practices are necessary for crop production

6. Why dry farming is important? Dry farming is an important agricultural practice in areas that lack sufficient water resources or are prone to drought . It can help increase crop yields and reduce the amount of water needed to grow crops. It also can help preserve the land while minimizing soil erosion .

7. Dryland farming Dryland farming is cultivation of crops in regions with annual rainfall more than 750 mm . In spite of prolonged dry spells crop failure is relatively less frequent . These are semi-arid tracts with a growing period between 75 and 120 days . Moisture conservation practices are necessary for crop production. However, adequate drainage is required especially for vertisols.

8. Rainfed farming Rainfed farming is crop production in regions with annual rainfall more than 1150 mm . Crops are not subjected to soil moisture stress during the crop period. Emphasis is often on disposal of excess water. These are humid regions with growing period more than 120 days

9. United nations economic and social commission for Asia and the pacific distinguished dryland agriculture mainly into two categories: dryland and rainfed farming. The distinguishing features of these two types of farming are given below.

10. Present status If 69.5 per cent is dryland and rainfed area. This area contribute about 42% of the food grains. Class Area (m ha) Percentage of total arable land Total arable 143.8 100 Dryland 34.5 24.0 Rainfed 65.5 45.5 Irrigated 43.8 30.5

11. The concept In modern concept, dryland areas are those where the balance of moisture is always on the deficit side . In other words, annual evapotranspiration exceeds precipitation. In dryland agriculture there is no consideration of amount of rainfall. It may appear quiet strange to a layman that even those areas which receive 1100 mm or more rainfall annually fall in the category of dryland agriculture under this concept.

12. To be more specific, the average annual rainfall of Varanasi is around 1100 mm and the annual potential evapotranspiration is 1500 mm . Thus the average moisture deficit so created comes to 400 mm . This deficit in moisture is bound to affect the crop production under dryland situation, ultimately resulting into total or partial failure of crops. Accordingly, production is either low or extremely uncertain and unstable which are the real problems of dryland in India.

13. Success of crop production in these areas depends on the amount and distribution of rainfall , as these influences the stored soil moisture and moisture used by crops . Amount of water by crop and stored in soil is governed by water balance equation ET= P-(R+S) When balance of the equation shifts towards right , precipitation (P) is higher then ET , so that there be waterlogging or it may even lead to runoff (R) and flooding. On the other hand, if the balance shift to left , ET becomes higher then precipitation , resulting in drought.

14. Characters of dry farming Uncertain, ill-distributed and limited annual rainfall. Occurrence of extensive climatic hazards like drought, flood etc. Undulating soil surface Practice of extensive agriculture i.e. Prevalence of mono cropping etc.. Very low crop yield. Poor marketing facility for the produce. Poor health of cattle as well as farmers.

15. Major problems of dryland Vagaries of monsoon Soil constraints Lack of suitable varieties Heavy weed infestation Socio-economic constraints

16. VAGARIES OF MONSOON Based on average annual rainfall, the country can be divided into three zones: low (less than 750 mm) , medium (750-1,150 mm) and high (more than 1,150 mm) rainfall zones. Dryland area is nearly equally distributed among the three. Areas with less than 1,150 mm (arid and semiarid) are the problem areas for crop production. Main characteristics (features) of rainfall influencing crop production are its variability, intensity and distribution , late onset and early withdrawal of monsoon and prolonged dry spells during the crop period .

17. Variable rainfall Annual rainfall varies greatly from year to year. Generally, higher the rainfall , less is the coefficient of variation . In otherwords , crop failures due to uncertain rains are more frequent in regions with lesser rainfall.

18. Intensity and distribution In general, more than 50 per cent of total rainfall is usually received in 3 to 5 rainy days. Such intensive rainfall results in substantial loss of water due to surface runoff . This process also accelerates soil erosion . Distribution of rainfall during the crop growing season is more important than total rainfall in dryland agriculture.

19. Late Onset and Early Cessation of Rains Due to late onset of monsoon , sowing of crop is delayed resulting in poor yields. Sometimes the rain may cease very early in the season exposing the crop to drought during flowering and maturity stages which reduces the crop yields considerably.

20. Prolonger dry spells during the crop period Long breaks in the rainy season are important features of Indian monsoon. These intervening dry spell when prolonged during crop period reduces crop growth and yield and when unduly prolonged crop fails.

21. SOIL CONSTRAINTS Alluvial soils occupy the largest area in dryland agriculture. Problems of crop production are so acute in these soils as they are in black and red soils . Major problems are encountered Vertisols , Alfisols and related soils and associated soils are mesh distributed in central and south India. The coastal areas have Alfisols , laterite and lateritic soil.

22. Alluvial soils Poor crop stand due to crusting and rapid drying of surface soil . Poor crop growth due to unreliable soil moisture supply, low moisture storage capacity due to shallow depth and drought spells during crop season. Low soil fertility due to low organic matter, poor nutrient statu . Land degradation from soil erosion and crusting .

23. Vertisols soil These soils commonly called as black soils are characterized by high clay content (30-70%) . Physical constraints such as narrow range of soil water content for tillage, tendency to become waterlogged and poor trafficability . Low soil fertility due to low N and available P. Land degradation from soil erosion and salt accumulation , especially in low-lying areas.

24. Inceptisols and Entisols These are commonly termed as alluvial soils . They have low water holding capacity and low nutrient holding capacity . Management of these soils for crop production is relatively easy compared to red and black soils . Soil erosion is, however, a problem leading to land degradation.

25. Heavy weed infestation This is the most serious problem in dryland areas . Soil environment ideal for crop growth is also congenial for weed growth. Weed seeds germinate earlier than crop seeds and suppress the crop growth. Weed infestation is severe in dryland agriculture due to continuous rains and acute labour shortage . Since crop performance under dryland farming is unpredictable , farmers hesitate to investment money for weed management leading to heavy loss in crop yield.

26. Socio-economic constraints The socio-economic status of dryland farmers, generally, will not permit them in adopting the recommended dryland technology. Major socio-economic constraints are: Lack of capital , support price for the produce , marketing and credit facilities make the farmers hesitate to invest on recommended technology. Most of the resource poor farmers opt for avoiding risk in dryland agriculture . Poor organisational structure for input supply in dryland areas.

27. Benefits of Dry Farming Allows farmers to produce crops in areas with limited water resources . Helps conserve water in the environment. Helps reduce soil erosion and increase water infiltration into the soil . Reduction in costs associated with irrigation.

28. Drought or moisture stress An extended period of deficient rainfall compared to normal rainfall of the region is called drought. Depending on the criteria used, drought is called as meteorological, agriculture or hydrological drought. Meteorological drought – It refers to substantial deficit of rainfall relative to average of the region . Indian Meteorological Department defines meteorological drought as a situation when there is a 25% decrease in the average rainfall for a given period in a region .

29. Agricultural drought – It refers to extended dry period in which lack of rainfall results in insufficient moisture in the root zone of the soil causing adverse effects on crops. Hydrological drought – It is extended dry period leading to marked depletion of surface water and consequent drying up of reservoirs, lakes, streams, rivers, cessation of spring flows and fall in groundwater levels. Dry spell is a rainless period more than 10 days in light soil areas and 15 days in heavy soil areas. Drought is prolonged dry spell resulting wilting or drying of crops . Severe from drought is called famine .

30. Moisture stress Soil moisture is the most limiting factor in dry farming and dryland farming situation . Stress is the result of action of external factors of an organism . Moisture stress indicates the action of lack of or excess of water on plants . The term moisture stress is generally used for deficit moisture conditions through it is applicable to excess moisture also. Moisture stress is most prevalent under dryland farming conditions .

31. Development of Moisture Stress Water deficits occur in the plant whenever transpiration exceeds absorption. It may be due to excessive water loss , reduced absorption of water from soil or both . After irrigation or rain, water deficits develop gradually and only for a very short period in the beginning. Though there is sufficient amount of soil moisture, water deficits develop due to higher transpiration than absorption especially on hot middays . This temporary wilting is known as incipient wilting or midday depression .

32. Under such conditions, stomata are open for a short period in the morning and evening and partially closed during the rest of the day. Stomatal closure occurs when leaf water potential approaches about -1.0 to 1.2 MPa in soybean . When the soil moisture reaches about -15 bars , plants show wilting symptoms most of the day, but do not die and it is known as permanent wilting point . Plants recover when irrigation is given or rain is received. If the soil moisture is further allowed to deplete to a level of - 6 MPa , plants die permanently and this is known as ultimate wilting point .

33. Drought tolerance Due to different drought avoidance mechanisms, plants are able to maintain favorable water balance and adverse effect of reduced water potential are not felt by the plants. In drought tolerance, water potential of plant is reduce and it adverse effects are felt. Drought tolerance can be defined as tolerance of the plants to a level of stress at which 50% of the cells die . The performance of higher plants depends upon the integrated function of may cells which is disturbed by drop. Drought tolerance is either by mitigating stress or by showing high degree of tolerance .

34. MOISTURE CONSERVATION IN DRYLANDS Annual rainfall in several parts of drylands is sufficient for one or more crops per year . Erratic and high intensity storms leads to runoff and erosion . The effective rainfall may be 65 per or sometimes less than 50 per cent . A number of simple technologies have been developed to prevent or reduce water losses and to increase water intake . Tillage Fallowing Mulching In situ moisture conservation

35. Tillage The surface soil should be kept open for the entry of water through the soil surface . Offseason shallow tillage aids in increasing rain water infiltration besides decreasing weed problems.

36. Fallowing Leaving the land fallow during rainy season and raise crops only during postrainy season on profile stored soil moisture. The main intention of fallowing is to provide sufficient moisture for the main postrainy season crops .

37. Mulching Mulching is a practice of covering the soil surface with organic materials such as straw, grass stones, plastics etc , to reduce evaporation, to keep down weeds and also to moderate diurnal soil.

38. In situ moisture conservation Bunding The first essential step in dry farming is bunding. The land is surveyed and level contours determined every hundred feet.

39. Broad Beds and Furrows (BBF) These are effective on black soils . Beds of 120-180 cm separated by furrows on grade are effective for in situ water conservation. Beds function as minibunds at a grade normally less than the maximum slope of the land. When runoff occurs , its velocity is reduced and infiltration opportunity time increased. Excess water is removed in a large number of small furrows . Crops are sown on broad beds

40. Compartmental Bunds They convert the area into small square/rectangular blocks . They are useful for temporary impounding water and improving the moisture status of soil . These can be made with bund formers or country plough. Size of bunds depend on inter bunded land area . Areas having a slope of 1 per cent or less suitable for compartmental bunding.

41. Dead Furrows Dead furrows on contour at 2.4 to 3.6 m are effective in shallow red soils of Anantapur (AP) for increasing the groundnut yield. Dead furrows are formed between two rows of the crop before start of heavy rains (September-October). They increase infiltration opportunity time besides reducing soil erosion.

42. Opening Ridges and Furrows Ridges and furrows are opened before onset of monsoon so that the flow of water may be reduced and erosion may be controlled to minimum. During rainy season, crops like maize, sorghum, pearl millet etc may be grown in the furrows and legumes like soybean, pigeonpea , greengram , blackgram , cowpea etc may be grown on the ridges.

43. Inter-row Water Harvesting under this system, furrows of about 30-40 cm width (15 cm deep) are alternated by ridges of 60-70 cm . It reduces runoff and water is conserved in furrows. It is, particularly, suitable for heavy textured soils . In light soils, crops are grown in furrows whereas in heavy soils, planting is usually on ridges to eliminate the problem of waterlogging.

44. Mechanism to improve water uptake Drought avoidance is promoted by well-developed deep root system with high efficiency to extract water from deeper layers of the soil. This mechanism is desirable if there is sufficient soil moisture in deeper layers for extraction. Water uptake can be improved by several mechanisms such as: Efficient root system Root-shoot ratio Increase in liquid phase Osmotic adjustment

45. Efficient root system Deep, well branched and rapidly growing root system helps in absorbing more moisture by exploiting higher volume of soil. It is an important morphological adaptation that helps in. drought resistance without losing productivity Variation in root length between varieties is related to differences in drought resistance. Genetic variability in root length is observed in soybean, wheat and tomato .

46. Root-shoot ratio If the roots are more compared to transpiring shoots , water balance can be maintained. Seedling establishment is particularly important in semiarid environments and root growth takes precedence over shoot during this stage. Drought increases root growth and root-shoot ratio which is an important mechanism of drought avoidance.

47. Increase in liquid phase To maintain high water potential in plants , not only uptake is important, but also conductance. Lowering of resistance to water can be achieved by increasing either diameter of xylem vessels or their number.

48. Mechanisms to conserve water Stomatal mechanism Increase photosynthetic efficiency Liquid deposits on leaves Reduction in leaf area and Leaf surface Effects of awns Water storage in plants

49. Resource development and utilization Important natural resources are rainfall, soil and plants . Resource development are their efficient use are two important aspects to achieve good and stable yield under dryland condition . The rainfall received in arid and semi-arid regions is to be stored either on the soil or in the soil.

50. Soil resources are developed by: Understanding the soil by proper grouping or classification . Rectifying the defects of the soil either by leveling, application of amendments. Increasing storage capacity of the soil. Plant resources are developed by selecting or breeding drought resistant varieties suitable for arid and semi-arid environments.

51. Dryland Farming Techniques Increase Water Absorption Prevent a crust at the soil surface . The beating action of raindrops tends to break down clods and disperse the soil. By tillage, create a rough, cloddy surface which lengthens the time necessary for the rain to break down the clods and seal the surface. For seed bed preparation in general, small seeds should have a finer, mellower bed than large seeds.

52. Reduce the Runoff of Water To the extent that waterlogging is not a problem, the runoff of water an attendant erosion must be stopped . Cropland should be as level as possible . All tillage and plantings must run across (or perpendicular to) the slope of the land. Such ridges will impede the downward movement of water.

53. Reducing the Loss of Soil Moisture Reducing Soil Evaporation Water in the soil exists as a continuous film surrounding each grain. As water near the surface evaporates, water is drawn up from below to replace it, thinning the film. When it becomes too thin for plant roots to absorb, wilting occurs. Shelter belts of trees or shrubs reduce wind speeds and cast shadows which can reduce evaporation 10 to 30 percent by itself and also reduce wind erosion. Mulching reduces the surface speeds of wind and reduces soil temperatures.

54. Reducing Transpiration All growing plants extract water form the soil and evaporate it from their leaves and stems in a process known as transpiration. Weeds compete not only for soil nutrients , but water as well and so their control is critical. Selection of crop is significant as well. Dwarf varieties have less surface and so lose less water. In dry farming, the number and spacing of plants is reduced so that fewer plants compete for soil moisture. The exception to this occurs when allowances for insect, bird, and rodent loss must be made at planting.

55. Conclusion Dryland agriculture requires different management practices than irrigated agriculture because of rainfalls variable and often unreliable nature. Crop must withstand long periods without water , followed by periods of heavy rains that can cause soil erosion . With careful consideration of soil type, crops and irrigation techniques, anyone with access to arable land can get into dry farming.

56. Reference John A WIDTSOE ( n.D. ) Dry farming for sustainable agriculture. T. yellamanda reddy ( n.D ) Principles of agronomy, dryland agriculture. S.R. reddy ( n.D ) Principles of agronomy, dryland agriculture.